Hi @mattkuae23 - Once you've linked the product code to an Origin account, it can't be used on another account. When you log into Origin, all games you've registered on that account will appear in the "My Game Library" section, regardless of what computer you log into. There is no need to register the product code again.
In situations like this, where you're not seeing the game listed, it was probably registered under an old Origin account name. Try logging in with any old email addresses you might have used back then. If you find the game under an old account, you can either play on that account or take steps to combine accounts.
